Zapp has been well marketed by AppZero. The marketing materials seem to imply that the Zapp platform enables creating application specific adaptor to extract the application and related configuration info along with user data and move to specified cloud. It is thus more appropriate for the ISV community. Any interested ISV can make a one time investment to develop an adaptor and move their application frequently from dev/test platform to production servers in various clouds.
CliQr uses a SaaS based delivery platform for such application virtualization and clearly targets ISVs. They are yet to commercialize their solution. Advocates of this technology maintain that it is a much cleaner approach for migrating to cloud. You only move the applications you need to move into cloud, not the server with all legacy apps. It is definitely a better approach for develop-once-and-onboard-to-multiple-clouds (and additionally to multiple devices for BYOD).
However, the problem with both approaches is that building an adaptor for each application to migrate to a specific cloud is costly and resource intensive. Imagine a real-life migration involving multi-tiered applications running with dependencies on multiple servers of various OS's. To add to the complexity, users like to migrate identical platforms on multiple clouds – one for production and another for backup.
It may be a good idea to clean up some legacy apps, but app by app migration is not a feasible strategy as no enterprise can afford disparity between two different target cloud platforms. The smart money's solution lies in server virtualization and cloud onboarding combination with the automated process for package update or removal.
